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   &#160;<span id="projectnumber">2.1.2</span>
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   <div id="projectbrief">Lightweight IP stack</div>
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<div class="title">ip4_frag.c File Reference</div>  </div>
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<div class="textblock"><code>#include &quot;<a class="el" href="opt_8h.html">lwip/opt.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="ip4__frag_8h.html">lwip/ip4_frag.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="def_8h.html">lwip/def.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="inet__chksum_8h.html">lwip/inet_chksum.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="netif_8h.html">lwip/netif.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="stats_8h.html">lwip/stats.h</a>&quot;</code><br />
<code>#include &quot;<a class="el" href="icmp_8h.html">lwip/icmp.h</a>&quot;</code><br />
<code>#include &lt;string.h&gt;</code><br />
<code>#include &quot;arch/bpstruct.h&quot;</code><br />
<code>#include &quot;arch/epstruct.h&quot;</code><br />
</div><table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="nested-classes"></a>
Data Structures</h2></td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">struct &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structip__reass__helper.html">ip_reass_helper</a></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
</table><table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="define-members"></a>
Macros</h2></td></tr>
<tr class="memitem:af920fb8127d00dd7a8b809afd28723fe"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="ip4__frag_8c.html#af920fb8127d00dd7a8b809afd28723fe">IP_REASS_CHECK_OVERLAP</a>&#160;&#160;&#160;1</td></tr>
<tr class="separator:af920fb8127d00dd7a8b809afd28723fe"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a510934accf149433bdcf683993e79080"><td class="memItemLeft" align="right" valign="top">#define&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="ip4__frag_8c.html#a510934accf149433bdcf683993e79080">IP_REASS_FREE_OLDEST</a>&#160;&#160;&#160;1</td></tr>
<tr class="separator:a510934accf149433bdcf683993e79080"><td class="memSeparator" colspan="2">&#160;</td></tr>
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<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:abc7017eb20983f372e81de7376ebec88"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="ip4__frag_8c.html#abc7017eb20983f372e81de7376ebec88">ip_reass_tmr</a> (void)</td></tr>
<tr class="separator:abc7017eb20983f372e81de7376ebec88"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a7debaa6366c0db4270d4f03219c75c05"><td class="memItemLeft" align="right" valign="top">struct <a class="el" href="structpbuf.html">pbuf</a> *&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="ip4__frag_8c.html#a7debaa6366c0db4270d4f03219c75c05">ip4_reass</a> (struct <a class="el" href="structpbuf.html">pbuf</a> *p)</td></tr>
<tr class="separator:a7debaa6366c0db4270d4f03219c75c05"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a70872fd4c7aefec6b4eef0707e1a371c"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="ip4__frag_8c.html#a70872fd4c7aefec6b4eef0707e1a371c">ip4_frag</a> (struct <a class="el" href="structpbuf.html">pbuf</a> *p, struct <a class="el" href="structnetif.html">netif</a> *<a class="el" href="structnetif.html">netif</a>, const <a class="el" href="ip4__addr_8h.html#a3d3b45daffbc15d65da236e31e621b7e">ip4_addr_t</a> *dest)</td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>This is the IPv4 packet segmentation and reassembly implementation. </p>
</div><h2 class="groupheader">Macro Definition Documentation</h2>
<a id="af920fb8127d00dd7a8b809afd28723fe"></a>
<h2 class="memtitle"><span class="permalink"><a href="#af920fb8127d00dd7a8b809afd28723fe">&#9670;&nbsp;</a></span>IP_REASS_CHECK_OVERLAP</h2>

<div class="memitem">
<div class="memproto">
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          <td class="memname">#define IP_REASS_CHECK_OVERLAP&#160;&#160;&#160;1</td>
        </tr>
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</div><div class="memdoc">
<p>The IP reassembly code currently has the following limitations:</p><ul>
<li>IP header options are not supported</li>
<li>fragments must not overlap (e.g. due to different routes), currently, overlapping or duplicate fragments are thrown away if IP_REASS_CHECK_OVERLAP=1 (the default)!</li>
</ul>
<p>Setting this to 0, you can turn off checking the fragments for overlapping regions. The code gets a little smaller. Only use this if you know that overlapping won't occur on your network! </p>

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</div>
<a id="a510934accf149433bdcf683993e79080"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a510934accf149433bdcf683993e79080">&#9670;&nbsp;</a></span>IP_REASS_FREE_OLDEST</h2>

<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">#define IP_REASS_FREE_OLDEST&#160;&#160;&#160;1</td>
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</div><div class="memdoc">
<p>Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller. Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA is set to 1, so one datagram can be reassembled at a time, only. </p>

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<h2 class="groupheader">Function Documentation</h2>
<a id="a70872fd4c7aefec6b4eef0707e1a371c"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a70872fd4c7aefec6b4eef0707e1a371c">&#9670;&nbsp;</a></span>ip4_frag()</h2>

<div class="memitem">
<div class="memproto">
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          <td class="memname"><a class="el" href="group__infrastructure__errors.html#gaf02d9da80fd66b4f986d2c53d7231ddb">err_t</a> ip4_frag </td>
          <td>(</td>
          <td class="paramtype">struct <a class="el" href="structpbuf.html">pbuf</a> *&#160;</td>
          <td class="paramname"><em>p</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">struct <a class="el" href="structnetif.html">netif</a> *&#160;</td>
          <td class="paramname"><em>netif</em>, </td>
        </tr>
        <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">const <a class="el" href="ip4__addr_8h.html#a3d3b45daffbc15d65da236e31e621b7e">ip4_addr_t</a> *&#160;</td>
          <td class="paramname"><em>dest</em>&#160;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td>
        </tr>
      </table>
</div><div class="memdoc">
<p>Fragment an IP datagram if too large for the netif.</p>
<p>Chop the datagram in MTU sized chunks and send them in order by pointing PBUF_REFs into p.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">p</td><td>ip packet to send </td></tr>
    <tr><td class="paramname">netif</td><td>the netif on which to send </td></tr>
    <tr><td class="paramname">dest</td><td>destination ip address to which to send</td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>ERR_OK if sent successfully, err_t otherwise </dd></dl>

</div>
</div>
<a id="a7debaa6366c0db4270d4f03219c75c05"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a7debaa6366c0db4270d4f03219c75c05">&#9670;&nbsp;</a></span>ip4_reass()</h2>

<div class="memitem">
<div class="memproto">
      <table class="memname">
        <tr>
          <td class="memname">struct <a class="el" href="structpbuf.html">pbuf</a>* ip4_reass </td>
          <td>(</td>
          <td class="paramtype">struct <a class="el" href="structpbuf.html">pbuf</a> *&#160;</td>
          <td class="paramname"><em>p</em></td><td>)</td>
          <td></td>
        </tr>
      </table>
</div><div class="memdoc">
<p>Reassembles incoming IP fragments into an IP datagram.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">p</td><td>points to a pbuf chain of the fragment </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>NULL if reassembly is incomplete, ? otherwise </dd></dl>

</div>
</div>
<a id="abc7017eb20983f372e81de7376ebec88"></a>
<h2 class="memtitle"><span class="permalink"><a href="#abc7017eb20983f372e81de7376ebec88">&#9670;&nbsp;</a></span>ip_reass_tmr()</h2>

<div class="memitem">
<div class="memproto">
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          <td class="memname">void ip_reass_tmr </td>
          <td>(</td>
          <td class="paramtype">void&#160;</td>
          <td class="paramname"></td><td>)</td>
          <td></td>
        </tr>
      </table>
</div><div class="memdoc">
<p>Reassembly timer base function for both NO_SYS == 0 and 1 (!).</p>
<p>Should be called every 1000 msec (defined by IP_TMR_INTERVAL). </p>

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